Add streaming task log support to KubernetesExecutor

[jason810496]

part of the streaming task log series

• depends on Add streaming task log support to BaseExecutor and FileTaskHandler #69299
• no conflict with Add running_pod_log_lines config option to KubernetesExecutor #69301 (any order after core)

Why

KubernetesExecutor.get_task_log materializes the whole pod log in the API server. Implementing the new BaseExecutor.get_streaming_task_log yields lines lazily into the bounded LogStreamAccumulator: ~11.6x lower peak heap growth (+2093.9 MiB vs +179.9 MiB) serving a ~415 MB running-task log (full benchmark in #69299).

What

• Implement get_streaming_task_log on KubernetesExecutor; get_task_log stays and delegates to it, so older cores keep working.
• Advertise supports_streaming_logs on KubernetesExecutor, CeleryKubernetesExecutor, and LocalKubernetesExecutor (the wrappers route kubernetes-queue tasks).
• Update log handler tests to assert the streaming read path for running tasks.

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Was generative AI tooling used to co-author this PR?

• Yes, with help of Claude Code Fable 5 following the guidelines

[Miretpl]

Looks good to me. I'd like a second review since I'm not familiar with how tests are done for the executors code.

[jason810496]

IIRC, the only CI failure should be resolved by other PR, so the static check failure it not related.

Traceback (most recent call last):
  File "/opt/airflow/scripts/in_container/run_provider_yaml_files_check.py", line 1117, in <module>
    all_parsed_yaml_files: dict[str, dict] = _load_package_data(paths)
  File "/opt/airflow/scripts/in_container/run_provider_yaml_files_check.py", line 170, in _load_package_data
    with open(provider_yaml_path) as yaml_file:
FileNotFoundError: [Errno 2] No such file or directory: '/opt/airflow/providers/apache/provider.yaml'

I will merge this.